Physiological analysis in coffee seedlings showing brown eye spot under different irrigation levels.

ABSTRACT Abstract: Brown eye spot is one of the major diseases that affect coffee seedling growth for causing defoliation and reducing the plant growth. The disease severity is higher when the coffee plant is subjected to water deficit. Using irrigation is an alternative to minimize the damage caused by this disease. The aim of this study was to evaluate the impact of this disease on the physiology of coffee plants as a function of the reduction in the irrigation level. The plants were subjected to three irrigation levels (0.1, 0.6 and 1.2 mm.day-1), inoculated and not inoculated with Cercospora coffeicola, in a completely randomized design with 35 replicates, totaling 210 experimental units. Coffee seedlings showing brown eye spot presented reductions in the minimum water potential and in photosynthesis as a function of the lower irrigation level, except for the irrigation level 0.6 mm.day-1. The activity of the antioxidant system in diseased seedlings was only higher under higher irrigation levels. Results proved that the presence of the disease increased water stress in coffee seedlings for reducing both water potential and efficient water use.